Finite size effect on nanomechanical mass detection: the role of surface elasticity

Abstract

Nanomechanical resonators have recently been highlighted because of their remarkableability to perform both sensing and detection. Since the nanomechanical resonators arecharacterized by a large surface-to-volume ratio, it is implied that the surface effect plays asubstantial role on not only the resonance but also the sensing performance ofnanomechanical resonators. In this work, we have studied the role of surface effect on thedetection sensitivity of a nanoresonator that undergoes either harmonic vibration ornonlinear oscillation based on the continuum elastic model such as an elastic beam model.It is shown that the surface effect makes an impact on both harmonic resonance andnonlinear oscillations, and that the sensing performance is dependent on the surface effect.Moreover, we have also investigated the surface effect on the mechanical tuning ofresonance and sensing performance. It is interestingly found that the mechanical tuning ofresonance is independent of the surface effect, while the mechanical tuning of sensingperformance is determined by the surface effect. Our study sheds light on theimportance of the surface effect on the sensing performance of nanoresonators.